‘Traditional’ Evidence Based Practice
(EBP)
Evidence-Based Practice (EBP):
Anatomy
Physiology
Pathology
Biochemistry
Psychology
etc.
how to inform your clinical
(practice) decisions with
the best, up-to-date
evidence
Evidence
Patient values
Rod Jackson
February 2011
‘Modern’ EBP emphasises ‘current’
clinical epidemiological evidence of
outcomes
Policy
Clinical (comorbidity)
considerations
Clinical Epidemiological* evidence
•  The accuracy of diagnostic tests
•  The power of prognostic markers
other Evidence
Policy
Epi Evidence
Patient values
•  The effectiveness of interventions
–  Therapy
–  Screening
–  Prevention
Clinical
considerations
* the study of the frequency of outcomes in groups of patients
Clinical evidence increasing so rapidly that
we all need EBP skills to keep up-to-date
MEDLINE 2006
1,600 articles / day
approx 100 new
trials published
every day
Bastian, Glasziou, Chalmers, (accepted for PLoS 2009)
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Evidence-Based Practice
Less that 10% of
published evidence
is worth reading
‘using the current best evidence from
epidemiology to help inform decisions’
•  more critically
•  more systematically
About 1/3 of
evidence
eventually refuted
or attenuated
The first 4 steps of EBP
1. Ask a focused question.
2. Access (systematically search for)
epidemiological evidence to help answer question.
3. Appraise evidence found for its validity, effect
size, precision (ideally all the relevant evidence)
4. Apply the evidence:
a. amalgamate the valid evidence with other
relevant information (patient/community values,
clinical/health issues, & policy context) and make an
evidence-based decision; and
b. Act (implement) the decision in practice
About 1/2 of
relevant evidence
is not implemented
GATE: Graphic Appraisal Tool for
Epidemiology
The 5th step of EBP
5.  Audit your practice:
check your actual practice against best
(evidence-based) practice
i.e. the gap between your evidence-based
decisions and your actions
1 picture, 2 formulas & 3 acronyms
2
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the 1st acronym = PECOT: the 5 parts of every
epidemiological study
the GATE picture: a framework for EBP
P
Participants
Exposure Group
E
C
O
Time
Comparison Group
Outcomes
T
Graphic Approach To EBP
All epidemiological studies can be hung on the GATE frame
EBP Step 1: ASK - turn your question
into a 5-part PECOT question
EBP Step 2: ACCESS the evidence –
use PECOT to choose search terms
1.  Participants (the patient problem)
2.  Exposure (e.g. a therapy)
3.  Comparison (there is always an alternative!
- another therapy or no treatment…
4.  Outcome (e.g. a disease you want to
prevent or manage)
5.  Time frame (over which you expect a result)
1.  Participants (the patient problem)
2.  Exposure (e.g. a therapy)
3.  Comparison (there is always an alternative!
- another therapy or no treatment…
4.  Outcome (e.g. a disease you want to
prevent or manage)
5.  Time frame (over which you expect a result)
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EBP Step 3: APPRAISE the
evidence
ACCESSING the best evidence to
answer your questions
Are you an effective searcher?
‘using the best evidence from
epidemiology to help inform decisions’
Are you familiar with MESH terms- the index to
PubMed?
•  more critically (using GATE)
•  more systematically
Are you familiar with Evidence-Based Guideline
websites? Cochrane reviews? Journals of
Evidence-Based summaries? Google Scholar?
PubMed?
doing a search is like doing a lab test
3
The 2nd acronym = RAMBO* : assessing bias
P
P
Recruitment
‘using the best evidence from
epidemiology to help inform decisions’
Allocation
E
E
C
C
O
T
EBP Step 3: Appraise evidence found for its
validity, effect size, precision
(ideally All the relevant evidence)
T
O
Maintenance
•  more critically
•  more systematically
Blind or
Objective assessment of
outcomes
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* Paul Glasziou
Total mortality from trials of β-blockers in 2° prevention after MI.
Cumulative meta-analysis of total mortality results from
trials of oral β-blockers after MI.
Black square & horizontal line
correspond to odds ratio (OR)
& 95% confidence interval
(CI) for each trial. The size of
the black square reflects the
weight of each trial. The
diamond represents the
combined OR & 95 CI,
showing a 22% reduction in
odds of death
Size of squares reflect
amount of statistical
information available at a
given point in time
Egger, M. et al. BMJ 1997;315:1533-1537
Egger, M. et al. BMJ 1997;315:1371-1374
EBP Step 4: APPLY the evidence by: a.
AMALGAMATING the relevant information & making
an evidence-based decision:’ the X-factor
©
4
X-factor: making evidence-based decisions
other Evidence
Policy
Epi Evidence
Patient or
community
values
Clinical or health
considerations
Epidemiologic
evidence
Step 4b
Clinical / health
considerations
Patient / community
preferences
ACT
Policy issues
expertise: ‘putting it all together’ the art of
practice
EBP pipeline: from evidence to
practice
The 5th Step: EBP 360°
1.  Ask a focused question.
2.  Access (systematically search for) epidemiological
evidence to help answer question.
3. Appraise evidence AND then meta-analyse
(systematically review) ALL relevant valid evidence.
4. Apply the best evidence:
a.  amalgamate the valid evidence with other relevant
information to make a good decision; and
b.  ACT on your decision
5. AUDIT your practice (i.e. check your actual practice –
‘actions’ - against ‘best’ evidence-based practice)
1. Evidence
= Quality Improvement
ACP Journal Club 2005; 142 (2): A8-A10
1. use evidence-based “electronic
decision support systems”
How can busy practitioners do EBP?
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2. use evidence-based guidelines (& EB text bks?)
3. use Systematic Reviews
MEDLINE 2006/day
1,600 articles
95 trials
4 reviews*
*Cochrane Database of
Systematic Reviews (SR)
per day
It is surely a great
criticism of our
profession that we have
not organised a critical
summary, by specialty
or subspecialty, adapted
periodically, of all
relevant randomised
controlled trials.
1 new SR
1 updated SR
Bastian, Glasziou, Chalmers, (accepted for PLoS 2009)
Final appraisal task: search for & appraise
SRs / meta-analyses using 3rd acronym
(FAITH)
•  Find appropriate studies?
•  Appraise selected studies?
•  Include only valid studies?
•  Total-up (synthesise) appropriately?
•  Heterogeneity adequated addressed?
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4. use individual studies
The evidence pyramid
This course is mainly about
studies and syntheses:
Evidence-based
guidelines
the foundations of the
evidence pyramid
Haynes RB (2001). Evidence-Based Mental Health 4:37-38.
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CATs (Critically Appraised Topics)
GATE-lite:
a rapid tool
for Step 3
(Appraisal)
A tool for documenting the steps of EBP
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